238 



ORTHOPTERA 



cells round certain points in the ventral plate. The segmentation 

 of the anterior parts is first distinct, and the appearance of the 

 appendages of the body takes place in regular order from before 

 backwards, the antennae appearing first ; the mandibles, however, 

 become distinct only subsequent to the maxiUae and thoracic 

 appendages. There are in the course of the development append- 

 ages to each segment of the body (he counts eleven abdominal 

 segments) ; the cerci develop in a similar manner to the anten- 

 nae ; the first pair of abdominal appendages — at first similar to 

 the others — afterwards assume a peculiar stalked form. The 

 abdominal appendages subsequently disappear, with the exception 

 of the ninth pair, which form the ventral styles, and the 

 eleventh pair, which become the cerci. The last ventral segment 

 is said to be formed by the union of the tenth and eleventh 

 embryonic ventral segments. 



As regards their Palaeontological forms Blattidae are amongst 

 the most interesting of Insects, for it is certain that in the 

 Carboniferous epoch they existed in considerable number and 

 variety. A still earlier fossil has been found in the Silurian 



sandstone of Calvados ; it con- 

 sists of a fragment (Fig. 133, 

 A), looking somewhat like an 

 imperfect tegmen of a Blattid ; 

 it was described by Brongniart 

 under the name of Palaeohlat- 

 Una douvillei, and referred by 

 him, with some doubt, to this 

 family. Brauer has, however, 

 expressed the opinion ^ that 

 the fragment more probably 

 Fig. 133. —a, Tegmm {^.) ot PaiaeoUaitina belonged to an Insect lilvC the 



doumllei; B, of EtoUattina manebach- „,„i^ „^- i j. -i ■ ■ r. 



ensis. (After Brauer and Scudder.) moie-CriCket, and m View of 



this discrepancy of authorities 

 we may be pardoned for expressing our own opinion to the effect 

 that the relic has no connexion with the Insecta. The fio-ure 

 given by Scudder ^ has not, however, so uninsect-like an app^ear- 

 ance as that we have copied from Brauer. Whatever may prove 

 to be the case with regard to PalaeoUattina, it is certain, as we 



' Ann. Bofmus. JJ'ien., i. 1886, p. 104. 

 - Zittel, Randb. Palaeont. I Abth. ii. 1885, p. 753. 



